The present invention relates to water cannons and, in particular, to a pneumatic control system for a water cannon.
The typical water cannon comprises a barrel assembly that has an opening or nozzle through which a body of water is driven by the application of a mechanical force. There are at least two types of barrel assemblies employed in water cannons. The first type includes a piston that is located within a barrel and used to apply a mechanical to a body of water located in the barrel. To elaborate, the operation of the piston involves: (a) positioning the piston at a location within the barrel that will allow the piston to be displaced such that water is forced through the opening; and (b) displacing the piston such that a mechanical force is applied to a body of water located between the piston and the opening so that the water is driven through the opening. An example of such a barrel assembly is illustrated in U.S. Pat. No. 6,119,955, which is incorporated herein by reference.
The second type of barrel assembly utilizes a barrel with a nozzle through which a body of water is driven (i.e., the opening) and a second end that is in communication with a channel that extends towards the nozzle. Typically, the barrel, channel and communication path between the second end of the barrel and the channel have a U-shape. An example of such a barrel assembly is illustrated in U.S. Pat. No. 3,722,819, which is incorporated herein by reference. In operation, the channel is used to carry a pressurized gas (typically, air) that is used to drive a body of water held in the barrel out of the nozzle.
The typical water cannon also comprises a control system that interfaces with the barrel assembly and operates: (a) to place the barrel assembly in a condition or state so a mechanical force can be applied to a body of water in the barrel of the cannon; and (b) to cause a mechanical force to be applied to the body of water that forces the body of water out of the opening of the barrel assembly. In many such control systems, electrical components are employed that are in the immediate vicinity of the water cannon and, as such, are subject to coming into contact with water. Such systems must typically employ a number of measures to prevent the electrical components of the control system from coming into contact with water and either becoming disabled or presenting a safety hazard to individuals in the vicinity of the water cannon.
The present invention is directed to a pneumatic control system for a water cannon that substantially avoids the need for electrical circuitry in the immediate vicinity of the cannon.
Generally, the pneumatic control system is applicable to water cannons whose operation involves at least two steps, the first step being the priming of the cannon, which at least includes the loading of a body of water into the barrel of the cannon, and the second step involving the xe2x80x9cfiringxe2x80x9d of the cannon such that the body of water is expelled from the barrel. One example of this type of water cannon is a cannon that employs a barrel assembly with a piston that is used to push a body of water out of the barrel of the cannon. With a piston-type of water cannon, the first step involves not only the loading of a body of water into the barrel of the cannon but also the positioning of the piston so that the piston can subsequently push the body of the water out of the cannon. The second step, with a piston-type of water cannon, involves moving the piston such that the body is pushed out of the barrel. Typically, the second step occurs in response to the actuation of a trigger. Another example of a water cannon whose operation involves at least two steps is the piston-less water cannon, an embodiment of which is shown in U.S. Pat. No. 3,722,819.
In one embodiment, the pneumatic control system comprises a valve that interfaces with the barrel assembly and is used to apply a fluid-related force to a body of water in the barrel in response to a pneumatic xe2x80x9cfirexe2x80x9d signal. In the case of a pistonless water cannon, the fluid-related force is applied directly to the body of water and the fluid-related force is typically in the form of a gas (e.g., air). For a piston-type water cannon, the fluid-related force is indirectly applied to the body of water. Namely, the fluid-related force is applied to the piston and then the piston transmits the force to the body of water. In this case, the fluid-related force can take either the form of a gas (e.g., air) or a liquid (e.g., water).
The control system further comprises a pneumatic trigger for producing the pneumatic xe2x80x9cfirexe2x80x9d signal that is applied to the valve. The pneumatic trigger is subject to a pneumatic enable/disable signal. To elaborate, when the pneumatic enable/disable signal is in the disable state, actuation of the pneumatic trigger does not cause the pneumatic xe2x80x9cfirexe2x80x9d signal to be produced. If, however, the enable/disable signal is in the enable state, actuation of the pneumatic trigger results in the production of the xe2x80x9cfirexe2x80x9d signal.
The pneumatic control system further includes pneumatic logic that operates to: (a) produce a disable/enable signal in the disable state so that the pneumatic trigger cannot be fired by actuation of the pneumatic trigger when the cannon is being fired or when the cannon is being primed; (b) produce a disable/enable signal in the enable state so that the pneumatic trigger can be fired when the cannon is not already in the act of being fired and the cannon is primed to fire; and (c) cause the valve to transition from the xe2x80x9cprimedxe2x80x9d state to the xe2x80x9cfirexe2x80x9d state in response to a xe2x80x9cfirexe2x80x9d signal from the pneumatic trigger.
In one embodiment, the pneumatic logic includes at least three pneumatic devices that each have at least one input for receiving a pneumatic signal (i.e., a gas signal) and at least one output for providing a pneumatic signal. The first pneumatic device receives a pneumatic signal from a third pneumatic device that is indicative of the state of the water cannon, i.e., the cannon is either in the act of firing or in the act of being primed. The first pneumatic device provides a first xe2x80x9cprimexe2x80x9d signal a predetermined amount of time after receiving the signal from the third pneumatic device that indicates that the water cannon is in the act of firing. The predetermined amount of time being an amount of time for the cannon to sufficiently complete a firing. As a consequence, the first xe2x80x9cprimexe2x80x9d signal is an indication that priming of the water cannon can commence.
The second pneumatic device receives a second xe2x80x9cprimexe2x80x9d signal that is produced by the third pneumatic device in response to the first xe2x80x9cprimexe2x80x9d signal. The second pneumatic device provides a pneumatic signal that is used to enable or disable the pneumatic trigger. The second pneumatic device operates so as to provide the pneumatic signal that shifts the trigger from a disabled state to an enabled state a predetermined amount of time after the second xe2x80x9cprimexe2x80x9d signal is received. Consequently, the second pneumatic device operates to produce a pneumatic signal that disables the trigger during priming of the water cannon and enables the trigger after priming of the water cannon is sufficiently complete.
The third pneumatic device receives a stream of gas that is distributed throughout the pneumatic logic and provides the basis for each of the pneumatic signals produced by the pneumatic logic. Further, the third pneumatic device receives the first xe2x80x9cprimexe2x80x9d signal provided by the first pneumatic device and the xe2x80x9cfirexe2x80x9d signal provided by the pneumatic trigger. Operation of the third pneumatic device is according to exclusive-or logic, i.e., the device is only capable of responding to one of the first xe2x80x9cprimexe2x80x9d signal and the xe2x80x9cfirexe2x80x9d signal at any point in time. Stated differently, the third pneumatic device is not capable of responding to the first xe2x80x9cprimexe2x80x9d signal and the xe2x80x9cfirexe2x80x9d signal at the same time. In operation, the third pneumatic device responds to the first xe2x80x9cprimexe2x80x9d signal produced by the first pneumatic device by providing the second xe2x80x9cprimexe2x80x9d signal to the second pneumatic device. The third pneumatic device responds to the xe2x80x9cfirexe2x80x9d signal produced by the pneumatic trigger by providing a pneumatic signal that causes the valve to release a pressurized gas or liquid into the barrel of the cannon and thereby xe2x80x9cfirexe2x80x9d the cannon. This pneumatic signal is also provided to the first pneumatic device to indicate that the state of the water canon, namely, that the cannon is in the act of firing.
In one embodiment, the first pneumatic device comprises a pneumatic timer that operates to produce the first xe2x80x9cprimexe2x80x9d signal at a predetermined amount of time after receiving a pneumatic signal indicating that the water cannon is in the act of firing. The predetermined amount of time being an amount of time for the water cannon to sufficiently complete a firing.
In another embodiment, the first pneumatic device comprises a pneumatic sensor/gate assembly that operates to produce the first xe2x80x9cprimexe2x80x9d signal after a sufficiently complete firing of the water cannon is detected by sensing that the water in the barrel of the cannon is at or below a predetermined level. In the case of a piston-type cannon, a sufficiently complete firing is detected by either sensing that the water is at or below a predetermined level or that the piston has traveled to a predetermined location in the barrel. In any event, the pneumatic sensor/gate assembly operates such that the pneumatic signal that indicates that the water cannon is in the act of firing xe2x80x9csetsxe2x80x9d the gate, i.e., causes the first xe2x80x9cprimexe2x80x9d signal to become inactive. A pneumatic signal produced by the sensor indicating that a sufficiently complete firing has occurred is applied to the gate and causes the gate to xe2x80x9cresetxe2x80x9d, i.e., causes the first xe2x80x9cprimexe2x80x9d signal to become active.
In yet a further embodiment, the second pneumatic device comprises a pneumatic timer that operates to produce the pneumatic signal that enables the trigger at a predetermined amount of time after receiving the second xe2x80x9cprimexe2x80x9d signal. In this case, the predetermined amount of time is an amount of time that is sufficient for the water cannon to have been primed.
In another embodiment, the second pneumatic device comprises a pneumatic sensor/gate assembly that operates to produce the pneumatic signal that enables the trigger after a sufficiently complete priming of the water cannon is detected by sensing that the water in the barrel of the cannon is at or above a predetermined level. In the case of a piston-type cannon, a sufficiently complete priming is detected by sensing either that water in the barrel is at or above a predetermined level or that the piston is at a predetermined location in the barrel, i.e., a location from which the piston can be moved to cause a body of water to be ejected from the cannon. In any event, the pneumatic sensor/gate assembly operates such that the second xe2x80x9cprimexe2x80x9d signal xe2x80x9csetsxe2x80x9d the gate, i.e., causes the pneumatic signal that disables the trigger to issue. The receipt by the gate of a pneumatic signal from the sensor indicating that a sufficiently complete priming has occurred xe2x80x9cresetsxe2x80x9d the gate, i.e., causes the pneumatic signal that enable the trigger to issue.
Another embodiment of the pneumatic control system is applicable to water cannons in which a body of water is loaded before firing but that already have a pneumatic trigger and valve. In this case, the pneumatic control system comprises the pneumatic logic without the valve and pneumatic trigger, and the pneumatic logic is retrofitted to the cannon.